Escapement mechanism



Sept. 18, 1945. c LURTZ 2,385,011

ESCAPEMENT MECHANISM Filed Sept. 3, 1941 2 Sheets-Sheet 1 IN V EN TOR.

Sept. 18, 1945. c. LURTZ 2,385,011

' ESCAPEMENT MECHANISM Filed Sept. 5, 1941 2 Sheets-Sheet 2 -INVENTOR.

Patented Sept. 18, 1945 UNITED STATES PATENT OFFICE ESCAPEMENT MECHANISM Carl Lurtz, Brooklyn, N. Y.

Application September 3, 1941,. Serial No. 409,331 2 Claims. (01. 58-117) This invention relates to an escapement device, and more particularly to that general type of construction wherein the two principal operat-. ing parts consist of a rotatable driving member and a co-acting pivoted vibratory driven member, adapted to operate either with or without association of a balance wheel or pendulum.

The primary object of the invention is to provide a mechanism of this general character, wherein inter-action between the two principal parts of the escapement, namely, the rotatable driving device and the vibratory driven device, may be achieved in such a manner that, in the course of one operative cycle of the escapement,

the vibratory device periodically arrests the driving device, which, when released, delivers an impulse to the vibratory device in only one direction of its vibratory movement; this escapement op-. eration being accomplished with incorporation of means for positively limitin to an acute angle the operativeness of that part of the vibratory device which directly interacts with the rotatable driving device, so that a separately pivotedoscillatory mass may be embodied with aid of a suitable and simple form of instrumentality whereby operation between said mass and the other parts of the escapement may be maintained.

By virtue of the more fundamental constructional and functional characteristics of the present invention it enables diverse forms of escapements to be built, and each of these forms may be constructed with embodiment of specific features of novel character. For instance, among the many modifications which may be constructed with incorporation of the invention, may be included pendulum escapements or balance wheel escapements of such design as may best be suited for time-controlling the operation of some form or other of. mechanism used in the industrial field.

The novel features of the present invention further enables various forms of escapement wheels or rotatable driving devices to be employed in operative conjunction with the vibratory device; accordingly, the driving device may consist of a rotatable disk having but a single driving member with aid of which impulse-action and arresting action may be effected with co-action of the vibratory device; or, the rotatable driving device may be provided with any number of driving elements. and arresting elements over and above one, up to a certainpractical limit.

Another noteworthy constructional feature of the present invention is that the impulse member of the vibratory device is in every cas disposed in such fulcrum relationship with respect to the arresting elements and the impulse elements of the driving device,that it enables the frictional resistance during unlocking operation to be overcome by the motion-producing instrumentality with a small proportion of its stored force.

Among the modifications made possiblewith embodiment of the present invention, may also be noted a construction whereby escapement operation of equal effectiveness is attainable irrespective of the direction of rotation of the driving wheel.

Other objects and adavantages of the invention will in part be pointed out and in part be apparent from the following detailed description and the accompanying drawings in which:

Fig. 1 is a plan view, showing a simple form of self-starting escapement embodying the principal ieaturesof the invention.

Fig. 2 is a modified construction wherein the vibratory lever is adapted for co-action with a balance wheel.

Fig. 3 is a side-view of Fig. 2.

Fig. 4 is another modification, illustrating de tailed constructional features of altered form in the several principal .parts of the escapement.

Fig. li'shows the invention incorporated in an escapement device adapted to operate, no matter in which angular direction the escape-wheel is driven.

Fig. 6 is another view of the device of Fig. 5, slightly modified, showing the operating parts of the escapement in an alternative "position.

Fig. 7'isia plan view of a modification in which operation of the device may be efiected with aid of a single pin in the rotatable driving device.

Fig. 8 is a fragmentary detail view, taken on the section line indicated in Fig. 7, showin the adjustable spring support for the vibratory device.

In the description of the present invention, and in the appended claims, the term vibratory device is used to generically designate that principal part of the escapement which is adapted for direct interaction with the rotatable driving device, or escapement wheel; and the term rotatable driving device is employed'to generically designate that principal unit which comprises the detent members and driving members on a revoluble shaft; further, the term oscillatory mass, when used in the following description; is intended to generically designate the balance wheel or/and pendulum; also, the mere mass of the vibratory device may be included in this meaning, that is, the extra weight whereby, with co-operation of a power means, such as a hairspring or magnet, equilibration of the period of vibration of the vibratory device may be effected.

Similar reference characters indicate corresponding parts throughout the several views of the drawings.

In one of the simpler forms of construction of the invention, as illustrated in Fig. 1, the vibratory device is represented in the form of a balanced lever I5, carried on the shaft I6, which in practice is journaled between two mechanism plates, one of which is shown in the drawing by the reference character H. The said lever embodies an arresting device or detent member I8 and a single impulse member I9. In this par,- ticular example of construction, all of the parts of the vibratory device are movable integrally within an acute angle and on a common axis; however, as hereinabove alluded to, a similar object may be achieved by having the several operating elements of the vibratory device separately pivoted, as will be described more specifically in a later part of this specification.

The vibratory device of Fig. 1 i adapted for operative interaction with the rotatable driving device, which, in the form shown, comprises the journally supported shaft and the wheel 2| with its ratchet teeth 22. The foreward acting face of the respective ratchet-formed teeth includes those two elements with aid of which impulse action and arresting action may be effected during vibration of the lever I5; whereas in several other forms, as disclosed in this specification, these two elements may be individually embodied in separate members of the rotatable driving device.

As shown in the drawings, the impulse member I9 is so disposed on the lever I5 that the said impulse member may be urged periodically in and out of driving engagement, respectively, with the teeth of the wheel 2|; while the detent member I8 may likewise be moved in and out of engagement with the respective teeth of the wheel. The disposition of the impulse member I9 and the detent member I8 in relationship with respect to each other and in relationship with respect to the path of the teeth 22, is such that when the impulse member I9 is being impelled, while the wheel 2| is driven in a clockwise direction, it causes the lever I5 to be thrown over a small angular degree, during which action the detent member I8 is carried into the path of the oncoming wheel-tooth for arresting the motion of the wheel 2I immediately after the impulse member I9 ceases to be driven by the driving device. To accomplish the arresting action, the detent member I8 is provided with a dead-beat face 23, thus affording the wheel 2| to be held stationarily until the detent member I8 is moved out of arresting position, and while this motion takes place, the lever I5 carries the impulse member I9 into driving engagement with the next driving tooth of the wheel 2I; accordingly, the said wheel may be periodically driven and arrested with co-action of the vibratory lever I5 and its two operating members.

For the purpose of urging the detent member I8 out of arresting position, some form of suitably connected power device is required. Since the vibratory motion of the lever I5 is limited to a comparatively small degree, this unlocking operation may be accomplished with aid of the force derived from a straight spring 24' of moderate length, which spring is shown connected with one end, by means of a friction sleeve 25, to the lever shaft I6; while the other end of said spring is held between two pins 26, supported on the shiftable device 21 whereby the effective power of the spring 24 may be adjusted for the attainment of a definite speed of escapement operation within certain limits.

The tension of the spring 24 is so adjusted that it exerts a torque in a counter-clockwise direction in the shaft I6, causing the lever I5 to be normally held in the particular angular position as shown in the drawings, in which position the detent member I8 is held clear of the path of the teeth 22. As a result, the device is enabled to start operating as soon as a certain definite amount of driving power is applied to the wheel 2I, because the impulse member I9 is in position for initial impulse action to take effect, whereafter the spring 24 urges the lever I5 back to impulse-receiving position, that is, after the wheel 2| has been arrested for a short period of time, subsequently to impulse-action, by means of the detent member I8; thereafter, the device is maintained in operation in the manner above set forth as long as the wheel 2| is supplied with driving force.

The effective mass of th lever I5, or vibratory device, is in this first form indicated by reference numeral 28. By virtue of the mass of the lever I5, coupled with the speed of motion and the influence of a given power of the spring 24, a definite period of oscillations may be established for governing the speed of rotation of the wheel 2 I.

-The device further embodies mean for positively limiting the angular motion of the lever I5 to less than Said motion-limiting means resides in part in the wheel 2I, whose teeth 22 are cut of n such depth that when the lever I5 is thrown beyond a certain normal operative limit within an acute angle, either the detent member I8 Or the impulse member I9, depending on the angular direction of motion of the lever, is moved in abuttal with the bottom of the intervening space between the respective teeth 22.

For the purpose of achieving this positive motion limiting characteristic of the vibratory device, there may be different forms of devices employed, as exemplified in the several modified constructions in the drawings.

A study of the mode of operation of the device of Fig. 1, will make apparent that the lever I5, when swinging in a counter-clockwise direction, is enabled to effect recoil motion in the wheel 2I to a small extent subsequent to impact of the impulse member I9 with a tooth of the wheel 2|. However, the device may be so constructed that this recoil action need not occur, as is best illustrated in the modified devices shown in Figs. 7 and 8.

The embodiment of means for positively limiting the operativeness of the vibratory device to a relatively small angle is of outstanding significanoe, since it is a feature which enables the vibratory device, in association with its other principal constructional characteristics, to be adapted, with incorporation of certain elements of construction, for interaction with a separately pivoted oscillatory mass, capable of detached angular motion, such as a free swinging balance wheel or pendulum: incidentally. it also enables almost any desired number of operating elements to be incorporated in the driving device of a given design. the number of such elements in the higher range being only limited by the size of the driving device to which it is restricted in practice.

A detailed account of a few modifications, representing constructions made feasible by virtue of the present invention, will be presented in the following description in connection with the several drawing illustrations.

InFigs. 2 and 3, the modified device is shown comprising an escapement wheel 213 having 30 teeth, instead of 60 as provided on the wheel 2| of Fig. 1. The wheel 2|B has its teeth adapted for proper interaction with the detent member l8 and the impulse member IQ of the lever IB for effecting operation in these two principal escapement members in a similar manner as in the device first described.

The supplemental constructional features embodies in the device of Fig. 2, reside principally in a certain part of the lever arm 29 and the means for its operative association with the balance wheel 30, which is carried with its shaft 3| on a separate pivotal support. Interaction between the lever I53 and the balance wheel 30 is attained with co-operation of the lever member 32, on the end of the arm 29, and the pallet 33 of said balance wheel. The arm 29 has a circularly shaped section 34 adapted to clear the way for the pallet 33 after the latter is given an impulse by the lever member 32 to set the balance wheel 30 in motion. Subsequently to such impulse action, the inter-connected hair-spring 35 exerts a counter-active force, causing the balance wheel to be reversed in motion before it completes one revolution. While the balance wheel 30 performs its detached oscillation, the lever |5B is maintained in a stationary angular position, holding the escapewheel 2 IB arrested with aid of the detent member I 8, as illustrated in the drawings.

The hair-spring 35 is so connected that, during inoperation of the device, it is enabled to urge the balance wheel 30, from the particular angular position shown in the drawings, sufiiciently in a counter-clockwise direction to cause the pallet 33 to engage the impulse face 36 of the lever member 32, and to compel the lever I5B to assume such angular position in which its impulse member I9 is held in the path of the teeth of the wheel 21B; as a result, the detent member I 8 is not in a position to prevent initial impulse action to take place, and since the impulse member I9 is disposed .at a considerable d stance from its fulcrum point, it enables the starting operation of the device to be unfailingly accomplished.

On the balance wheel shaft 3| a cylindrical section is cut away, as shown by reference numeral 31, so as to allow the lever member 32 to pass across the axis of said shaft while the pallet 33 is in driving engagement with the member 32 of the arm 29. At the moment the impulse member l9 of the lever I5B strikes a tooth of the escapement wheel 2 IB, the balance wheel 30, as it swings in a counter-clockwise direction, is brought quickly to a stop by the resisting force of the driving wheel; only to be again impelled in a clockwise direct on until the impulse member l9 becomes released from the driving tooth of the wheel 2IB. The aforementioned quick stopping action of the balance wheel, in one given direction, may be avoided if the device is constructed on'lines as revealed in Fig. 7.

As regards the mechanical advantages secured with aid of the constructional features of the device of Fig. 2, it will be-noted that this is due in part to the effectiveness of the leverage of the pallet 33, wh ch leverage is of such character that it enables the frictional resistance of the detent member l8 to be overcome with but little con sumption of the stored energy of the balance wheel 30, when it returns to swing the lever I5B in a counter-clockwise direction; incidentally, a lessening in the frictional impediment on the dead-beat face 23 of the detent member I B is also device is indicated in dotted lines in Fig. 3, bear ing the reference character MB.

In comparing the device of Fig. 2 with the device of Fig. 1, it will be evident that in essence the principal parts of the escapement construction are analogous; manifestly, in Fig. 2 the supplementary power-means for urging the arresting device, or detent member, out of arresting position is embodied with an oscillatory mass having a detached motion, in contradistinction to the device of Fig. 1, where the oscillatory mass and the supplementary power-means form an integral part of the vibratory device, which in both cases embodies a single impulse member and a detent device operatively limited in vibration to an acute angle; the attribute of said single impulse member being to move in and out of driving engagement with the rotatable driving device whereby impulse power is delivered for the operation of the mechanism. These salient features possess distinguishing characteristics embodied in all the modifications disclosed in this application.

The device illustrated in Fig. 4 comprises detailed constructional features of modified form in all three principal parts of the escapement mechanism, viz., the rotatable driving device, the vibratory device and the separately pivoted oscillatory mass. One of the objects of the embodiment of the modified features in this device is to effect a diminution of wear in the interengaging parts and to lessen the noise which usually originates from contact making of the interengageable operating parts in the absence of any special provision for the abatement of the sound. To accomplish the aforementioned object, certain parts of the escapement device, as shown in the drawings, are constructed of non-metallic material, such as Bakelite or some other suitable form of non-resonant material, and these parts are so arranged in relation to other metallic operating parts, that during operation of the escapement device, contact may be established only between metallic and non-metallic operating parts.

Considering nOW the details of construction of .the device mentioned in the preceding paragraph: The rotatable driving device, as shown in the drawings. consists of two major operating parts, namely, the pinion 39, having driving teeth 40. made of steel or some other suitable metal, and the large wheel 4|, having detent teeth 42, made of Bakelite or any other suitable material capable of absorbing most of the sound vibrations instead of enforcing them. The teeth 40 of the pinion 39 are adapted to serve solely as driving members, and the teeth 42 of the large Wheel 4| are adapted to perform the function of arresting elements for inhibiting the motion of the rotatable driving device in co-operation with the detent member 43 of the vibratory device; the detent member 43 is fashioned from metal and swings integrally'with the lever 44 which is fabricated from fiat stock of Bakelite material. As seen in the drawings, the left-hand branch of the lever 44 is provided with an operating member 45 adapted to be swung over a small angle in a counter-clockwise direction by action of a tooth of the pinion 3!! while in drivin engagement with the impulse member 48 on the lever 44 at its right-hand side. After a short distance of angular motion of the pinion 39 in a counter-clockwise direction, its driving tooth becomes disengaged from the impulse member 46, which then lies in such position that it may be urged into engagement with the next tooth of the pinion 39 when the lever 44 is swung in a clockwise direction. At that moment when the driving tooth of the pinion 39 escapes from the impulse member 43, a detent tooth of the wheel 4i drops on the detent member 43, thus inhibitin the motion of the rotatable driving device up to the time when by reason of clockwise mot on of the lever 44 the detent member is moved out of the path of the teeth of the wheel 4!, where after the impulse member 46 is again in position to be driven by the pinion 39.

During vibration of the lever 44, its operating member 45 at the left is interacting with the balance wheel 41, which, like the two first described principal parts of the escapement, is made up of metallic and non-metallic operating parts; one of these operating parts is shown in the form of a Bakelite disk 48, held tight to the metallic part of the oscillatory mass by means of the rim 49. Centrally in the Bakelite disk 48 is made an outcut 50 having a circular detent edge 5| adapted to block the path of the guardpin 52 of the lever 44, during detached oscillatory motion of the balance wheel 41, so that for the duration of this oscillatory motion, the lever 44 is unable to swing away from the definite angular position in which the detent member 43 is held in engagement with a tooth of the wheel 4|.

Close to the balance wheel shaft 3IB, a pallet 53 is fixed; said pallet is provided with a, first impulse face 54 and a second impulse face 55; the first impulse face 54 is adapted to be maintained in driving contact with the driving face 56 of the lever-member 45, and the second impulse face 55 of the pallet is adapted to move into rolling contact with the operating edge 51 of the lever when swinging over a definite angle. The rolling contact operation of the second impulse face 55 takes place at such time when the pallet 53, upon return motion of the balance wheel 41, urges the lever 44 in a clockwise direction beyond its angular position shown in the drawings; as a result, the first impulse face 54 of the pallet is enabled to quit contact with the operating face 56 of the lever 44 as soon as the second impulse face 55 of the pallet comes in driving contact with the operating edge 51 of said lever; in this manner, injurious sliding friction between said first impulse face 54 and said operating face 56 may be avoided because the driving action takes place across the line of center within a relatively small angle as shown in dotted lines, and indicated in the drawings by reference numeral 58. The constructional features for the accomplishment of the last mentioned driving action, reside principally in the particular form of the pallet 53 and also the form of that part of the operating member 45 wherewith the pallet may make contact; specifically stated. the pallet 53 has that portion on which the first impulse face 54 is disposed projected into a receded section of the operating member 45 bearing the operating face 56, whereas the operating edge 51 of said member is disposed farther forward and lies on such an angle with respect to the angular disposition of the second impulse face 55 of the pallet that the latter is enabled to travel in perfect rolling contact with the lever 44 when engaging its operating edge 51.

The outcut of the disk 48 includes the elongated part 59 which is adapted to permit entrance of the guard pin 52 when the lever 44 is moved angularly while in driving engagement with the pallet 53.

The detent member 43 of the lever 44 is a small end-portion of the rectangular bend, formed from the fiat steel piece 60, which is supported on the hub-member 6| of the lever shaft 16. An outcut B2 of the lever 44 is adapted to support a projecting portion of the detent member 43, and this outcut is also suitable for holding a liberal amount of lubricant for the detent elements of the device.

A further modified feature in the construction of Fig. 4, resides in the adjustable means for varying the effective power of the hair-spring 35. In the drawings, the outer end of the hairspring is shown connected to end of the arm 53 which is frictionally held on the supporting 'rame (not shown) of the escapement, and is adapted to swing on a pivotal point in line with the axis of the balance wheel shaft 3|B. The inner end of the hair-spring is secured to said balance wheel shaft, hence, when the arm 63 is shifted to the left or right, the degree of restoring force of the hair-spring on the balance wheel is varied in proportion to the degree of such shifting operation, and accordingly, the number of oscillations of the balance wheel within a definite period may be established with disposition of the arm 63 in a definite angular position Briefly reviewed, the operation of the last described device is as follows: From the position of rest of the escapement parts as shown in the drawings, the driving pinion 39, linked to a driving force, imparts an impulse to the lever 44 which is transmitted to the pallet 53, causing the balance wheel 41 to be thrown in a clockwise direction; and subsequently to motion of the lever 44 over a small angular degree in a counterclockwise direction, it is stopped by the balance wheel shaft 3IB when the stop member 64 of the said lever strikes against a cylindrical portion of said shaft. In this angular position of the lever 44, its detent member 43 checks the motion of the wheel 4|, while the guard pin 52 with co-operation of the circular detent edge 5| constrains the lever 44 to a definite angular position until the pallet 53, with its balance wheel 41, returns to urge the lever 44 in a clockwise direction so as to cause the detent member 43 to move out of arresting position and to cause the impulse member 46 to move into the path of the next driving tooth of the pinion 39 for the succeeding impulse action to take effect as soon as the wheel 4| becomes released from the detent member 43 of the lever 44.

The escapement construction shown in Figs. 5 and 6, embodies a modified form of vibratory device in which such detailed constructional features are incorporated that the escapement device is rendered capable of operating equally well irrespective of the angular direction in which the operativelyassociated rotatable driving device happens to be driven. In the escapement mechanism which will presently be described, there are embodied a few additional modified constructional features, but as regards the general aspect of construction, it will become apparent as the description proceeds that those distinguishing functional and constructional characteristics whereby the different species shown in the drawings are interrelated, are also included in the device of Figs. and 6. In this connection, it may here be pointed out that the vibratory device of Fig. 5 may be regarded as consisting of two identical halves, each half being an individual operating unit possessing all the necessary operating elements whereby interaction with the other principal parts of the escapement may be achieved, viz., one of these halves of the vibratory device becomes operatively engaged with the escapement mechanism when the rotatable driving device is being driven in one given direction; while the operating elements of the other half of the .vibratory device are brought into operative relation with the rotatable driving device only then when the latter is being driven in a contrary direction to the direction first named. With respect to the above remarks, it should be borne in mind that the vibratory device, although provided with two operating faces on its impulse member, is adapted to operate with only one of these operating faces during successive cycles of operation of the escapement device.

Attention is now directed to the details of construction. Of the supporting frame for the escapement shown in Fig. 5, the mechanism plate I and the bracket |1D are shown in the drawings. The vibratory device or lever 65 is carried on the shaft 13 which is journalled with one end in the bracket |1D so that the large balance wheel 66 may be free to swing in the intervening space between the said bracket and the mechanism plate |1C. In the form shown, the teeth 61 of the escapement wheel 68 serve the purpose of members with co-operation of which rotative motion of the escape-wheel may be arrested periodically, that is, each time after the lever 65 has delivered an impulse to the balance wheel 66. Intermittent impulsion to the lever 65 is imparted by means of the respective studs or pins 69, carried on the wheel 68.

Each stud 69 lies on a radial line terminating in the point of its adjacent detent tooth of the wheel 68, and this arrangement of the operating members on said wheel provides one of the elements by virtue of which interaction between the vibratory device and the rotatable driving device may be achieved in the characteristic manner which will be elucidated hereinafter.

The vibratory device or lever 65 is provided with an impulse member 10, which member, when the escapement parts are in a position of rest, comes to lie within one of the spaces intervening between the pins 69; similarly, the impulse pin 1| of the balance wheel 66, when in its normal position, comes to lie in the intervenin space between the fork-branch 1 5 and 8| of the lever 65. During inoperation of the device, a detent tooth of the wheel 68 occupies a position at a small distance to the left of the lever shaft 13, and another detent tooth of said wheel is disposed at a definite distance from said shaft at its right-hand side; consequently, as soon as driving power is applied to the escapement wheel, either in a clockwise or a counter-clockwise direction, it enables the wheel to move over a small angular distance and to impart an impulse to the lever 65 by means of one of the flanking pins 69 in whose path the impulse member 10 of the lever happens to project.

In Fig. 5, the movable parts of the device are shown'in aposition of operation, while driving power is being applied to the escapement wheel 68 in a clockwise direction. The wheel 68' is shownheld arrested, and the lever 65 is disposed in an angular positipn in which its impulse member 10 is out of the path of the driving pins 69; the balance wheel 66, after having received an impulse, swings free in a clockwise direction up to a certain limit and is then returned by force of the hair-spring 35B. In case the balance wheel is overthrown due to excessive impulse power, then the impulse pin 1| is adapted to strike the flank 14 of the fork-branch 15, as shown by the position of the pin 1| in dotted lines in Fig. 5. During detached angular motion of the balance wheel, the lever 65 is compelled to remain in a stationary position because the notched roller 16 of the balance wheel shaft 3|B prevents motion of the lever in one direction, and the stop arm 19, when abutting one or more of the driving pins 61, prevents motion of the lever in the other direction. But as soon as the pin 1| of the balance Wheel is carried into reengagement with the impulse face 18 of the fork 12, the fork-branch 15 is free to enter the outcut 11 of the roller 16, thus permitting the lever 65 to be swung in a clockwise direction so as to effect subsequent release of the escapement wheel 66 for its next impulse action.

As may be seen through the broken part of the lever 65 in Fig. 5, the detent tooth 61A rests on the cylindrical stop portion of the lever shaft 13; at this section of the said shaft, part of its cylindrical portion is cut away, as indicated by reference character 80, so as to provide a free path for the wheel 68, enabling it to move forward as soon as the lever 65 is swung back to its normal position, whereupon the impulse member 10 strikes the driving pin 69B causing the lever 65 to be subsequently again swung in a counter-clockwise direction for a repetition of escapement operation to take effect as above set forth.

In extreme cases, the lever 65 may be urged to its angular position shown in Fig. 6, while the driving tendency of the wheel 68 is still in a clockwise direction; this illustration reveals that no matter how far the pin 1| is carried to the right of its normal position solely by force of the rotating balance wheel shaft 3|B, it does not cause the escapement parts to be jammed to an inoperative position, because if this pin 1| with its balance wheel or pendulum 8-4 should continue to swing in a counter-clockwise direction from its angular position shown in Fig. 6, then the roller 16 is in position to hold the lever 65 so that the pin 1| may re-enter the fork 12.

Complete cycles of operation may be performed by the escapement device in identical fashion as hereinabove described, in case the escapement wheel 68 is driven in a contrary direction, that is to say, in a counter-clockwise direction. During this alternative operation of the device, the forkbranch BI is adapted to serve as the impulse member for the pin 1| .of the balance wheel, thus the latter is impelled in a counter-clockwise direction by the lever 65, and in this case, the righthand arm 82 of the lever is intercepted by one or more of the pins 69 after cessation of impulse action, at which time a detent tooth of the wheel 68 comes to rest on the right-hand side of the lever shaft 13.

As shown in the drawings, the arresting faces of the lever-shaft 13 are disposed on an arc of comparatively small radius; hence, in order to enable a substantial portion of the operative arresting face to be moved into the path of a detent tooth of the wheel 68, the escapement device is so constructed as to cause the lever 65 to vibrate over an angle which is considerably larger than the operative angle with which the vibratory device of the first described forms is associated. If desired, the angle of vibration of the lever 65 may be further increased, if, for example, the impulse member ID is made longer than shown and if a smaller number of operating members are provided on the wheel 68, in .which event, suitable changes are also incorporated in the fork of the lever 65 and in the interacting instrumentality of the balance wheel.

It will be noted, that although the impulse member ID of the device of Fig. 5 is set much closer to its axis of swing than the impulse member of the vibratory device disclosed in other illustrations in this application, nevertheless, the arrangement of the impulse member I is such in relationship with respect to the operating members of the wheel 58 and the arresting elements of the lever 65, that said impulse member is adapted, while in drivin engagement, to move within an acuate angle over a path much larger than the path over which the arresting elements of the lever 65 are enabled to move during any part of operative cycle; and a study of the disclosure in this specification will show that in this and several other respects, all the different species of construction of the present invention are co-extensive.

In Fig. '7, the escapement device, embodying the essential features of the invention, is represented in a modified and simple form; the mechanical combination, illustrated in this drawing figure, comprises, like all the other species disclosed in this application, the rotatable driving device, indicated by reference character ZIE, adapted to impel the co-acting vibratory device, bearing reference character IEC, in one definite angular direction intermittently, and to be arrested periodically with aid of elements in the vibratory device whose operativeness is positively limited to an acute angle; with the vibratory device is operatively associated the oscillatory mass, indicated by reference numeral 283, including a power device 24B, adapted to impart a restitution force to the vibratory device IC whenever the latter is swung away from a definite normal angular position.

As regards the more specific features of the device of Fig. 7, these features are most closely related to the features of the modification disclosed in Fig. l of the drawings in this application. However, the rotatable driving device ZIE of Fig. '7 is provided with only one driving member, shown in the form of a pin I4I, secured to the revoluble plate I42 which is carried on the pivotally supported shaft 20B. The vibratory device or lever I5C is provided with a suitably constructed operating member I43, adapted to periodically intercept the pin MI, and to intermittently receive an impulse from said pin when the latter with its rotatable supporting plate I42 becomes released for driving action.

As shown in the drawings, the pin MI is held arrested on the stop-face I44 of the detent member I45 which is-a part of the operating member I43. The stop-face I44 is disposed on a plan concentric with the axis of swing of the lever I5C, so that the pin I4I, while resting on said stop-face, is not enabled to impart angular motion to the lever I50; but when the said lever is swung counter-clockwise, as viewing the drawings, by force of the spring 2413 to cause the detent member I45 to move downward suiiiciently so that the pin MI is permitted to escape from the stop-face I44, then the plate I42 is free to rotate in a clockwise direction, and after covering a definite angular distance, the pin I is enabled to strike the impulse edge I46 of the operating member I43, thus eiiecting reversal in the angular motion of the lever I50; and since there is no further motion-inhibiting obstruction in the path of the pin I4l up to the end of a complete arc of its motion, the rotatable driving device is brought to a momentary stop only at the instant when the said pin is intercepted by the detent member I45, but the latter is quickly drawn away from its motion-inhibiting position by force of the spring 2413 so as to allow the pin I to perform its next impulse action.

The function of the spring 24B may also be achieved by means of a magnet which is indicated by reference character I41, provided that part of the lever I5C which is exposed to influence of.

the magnetic field is made of ferrous substance. The electric conductor I48, shown surrounding the magnet I41, serves to illustrate that an electro-magnet may be employed, if desired, instead of the permanent magnet I4I. An alternative form of magnet device is shown in dotted lines at the right-hand side of the lever-shaft I6; this arrangement of power-means may be substituted for either the magnet I41 or the spring 24B.for the purpose of imparting restitution force to the vibratory device to enable the detent member I45 to be urged out of motion-inhibiting position. In this alternative construction, an adjustable arm I51, held on the mechanism plate IID, is provided for the support of the permanent magnet I4'IA, which has its polar region disposed in the field of magnetic repulsion of another permanent magnet I58, carried on the member 28B of the lever I5C, thus setting up a force tending to swing the vibratory device to a limited extent in a counter-clockwise direction.

In the device of Fig. '7, including Fig. 8, the spring 24B is shown made in the form of a spiral spring whose outer end is connected to the arm I49 which swings integrally with the lever I50, and the inner end of said spiral spring is connected to the stationary hub-piece I50 which is secured to the end-portion of the stem l5l; this stem is frictionally supported on the mechanism plate I'ID in such a manner as to enable the stem I5I with its hub I50 to be manually rotated to that particular angular position wherein the adjusted tension of the spring 2413 is capable to effect the necessary torque in the shaft I6 so as to enable the lever I5C to perform its function properly. The pivotal end of the shaft I6 is journalled in an axial hole I52, which hole is made on the end-portion of the stem I5I, as shown in dotted lines in Fi 8.

In combination with the lever I5C is further shown an additional member I53 which is provided with a guide member I54, adapted to compel the lever 15C to remain in a definite angular position during the latter part of angular motion of the pin I4I so that the detent member I45 is held in proper position to intercept the said pin at the end of its motion over a complete arc, no.

matter how slow the rotatable driving device is being driven. However, under normal conditions of operation of the escapement device, the additional member I53 is not needed, because by reason of the time it requires for the lever I50 to be reversed in its motion, after having received an impulse, the detent member I45 is always disposed in the path of the pin I4I at the proper moment to enable motion-inhibiting operation to' be effected in the rotatable driving device if the latter is driven with sufficient speed up to the time when the pin I4I has very nearly completed its uninterrupted periodic angular motion.

The lever I5C is definitely limited in its operativeness to an angle of less than 90, and also embodies, like all the other species shown in the drawings of this application, a detent device and a single impulse device whose operating elements are disposed at an appreciable distance away from the operating elements of the detent device, so that a comparatively strong motion-producing force may be delivered to the vibratory device, which device, by virtue of the characteristic arrangement of its operating parts, is enabled to urge the detent device out of motion-inhibiting position with aid of but a small proportion of the force which is imparted to the vibratory device during operation or the escapement mechanism. Further, in order to prevent the device from being rendered inoperative in case the impulse power of the mechanism is in excess of that required for the normal operation of the mechanism, or in case some other force prevail to produce such tendency, there is included in the escapement construction positive means for inhibiting the angular motion of the lever I5C when swung within an acute angle a definite degree beyond the angle of its normal vibration, In the device of Fig. '7 this object is achieved with co-operation of the shaft 20B, which is adapted to intercept the edgeportion I55 of the operating member I43 when swung in a counter-clockwise direction up to a certain limit; while in a contrary direction, the lever I5C is limited in its angular motion when the edge-portion I56 of the operating member I43 is moved in abuttal with the shaft 203. Thus, with the embodiment of the distinguishing features a briefly recited in this paragraph, the device is rendered capable by virtue of its novel features to perform mechanically advantageous functions in connection with various forms of escapements wherein diverse detailed constructional features may be incorporated for the attainment of escapement operation, such as is best suited for the accomplishment of the desired result in association with a particular mechanism in the industrial field.

Having now particularly described and ascertained the nature of my invention, I would state in conclusion that, while the illustrated examples constitute practical embodiments of my invention, I do not desire to be restricted to the detail of construction and arrangement of parts of the various constructions in the accompanying drawings, since manifestly they can be considerably varied without departure from the spirit of the invention.

What I claim as new and desire to secure by Letters Patent in the United States, is:

1. In an escapement mechanism, a rotatable escapement wheel having operating elements, a vibratory device having an impulse-member movable periodically into and out of driving engagement With the operating elements of the escapement wheel; said impulse-member being arranged to move over a limited arcuate path of a larger radius than the radius of the arcuate path of the said operating elements; a detent-member on the vibratory device adapted for arresting the movement of the wheel while the said impulsemember is out of driving engagement with said escapement wheel; the detent-member being arranged for movement over a portion of an arc of smaller radius than the radius of the arcuate path over which the said impulse-member is movable; a weighed mass operatively associated with the vibratory device for determining the periodicity of the latter, an operating spring interconnected vq'th the mass for imparting restoring force thereto and to the vibratory device whenever the former and the latter are swung away from a normal angular position, and an instrumentality interactive between the vibratory device with its weighed mass and the escapement wheel, adapted to enable the said operating spring to urge the said detent-member out of motion-inhibiting position while the vibratory device swings in one angular direction for carrying its impulse-member into the path of an operating element of the escapement wheel to be subsequently driven thereby in the opposite direction while the said detent-member is being carried into the path of an operating element of the wheel to arrest its motion on or about the time the said impulsemember of the vibratory device ceases to be driven.

2. In an escapement mechanism, a rotatable wheel having operating teeth, a balance oscillatable over a limited angle, means for effecting restoring force in the balance when swung away from its normal angular position, a pallet on the balance, an oscillatory lever having a, driving member adapted to engage said pallet to drive it in one direction and to be driven thereby in the opposite direction over a limited angle, a detent-member on the lever movable into the path of the teeth of the rotatable wheel while said driving member of the lever drives said pallet to enable the wheel to be subsequently arrested by said detent-member, and an impulsemember on the lever arranged to move into driving engagement with a tooth of the wheel whenever the detent-member is urged out of motionarresting position while the pallet drives the driving member of the lever in one direction to enable the latter to be subsequently impelled in the reverse direction by the rotatable wheel, whereby an impulse is delivered to the balance in only one direction of its oscillatory movement.

CARL LURTZ. 

